I’ve only camped a few times in my lifetime, but those were fun memories. One was up in the North Cascades on a backpacking trip with Mount Baker as best backdrop under the starry skies.
The other memorable backpacking trip was in Mount Rainier National Park. They now are doing a reservation system for the most of the area. There are some hikes that don’t require you to go through the main entrances though. See here for more information: https://www.nps.gov/mora/planyourvisit/timed-entry-reservations.htm
Lucky invitations from friends that won the Enchantment lotteries were the other two camping experiences that were awesome. You definitely need to do some hikes in that area and jump or take a dip in the lake (only if it is hot enough out).
Here are a few other resources to bookmark: